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Help! Antiskate with only a weight...no dial, and she's skating away!

I have a project rpm 10 carbon with 10cc evolution tonearm that has a weight on a string for antiskate. There are three notches on which to attach the string based upon the tracking force range of the cartridge. I currently have an ortofon cadenza bronze tracking at 2.5g and have the antiskate weight in the appropriate notch (according to the Pro-ject manual) from which it hangs. The table is level--checked and adjusted to ensure. The tracking force is at 2.514g (the range for the cadenza is 2.2-2.7 with 2.5 suggested by ortofon) checked with a digital scale (Riverstone Audio digital scale). The soundstage sounds great, vocals are centered, other instruments are placed in space according to the recording... Also the alignment was carefully set up using the WallyTractor and is spot on. 

But sometimes when I lower the stylus to the lead in groove, it will slide very quickly towards the spindle as though no antiskate were present (it doesn’t skip over the record, it falls into the first song groove--and yes I have confirmed that the stylus is present). But it’s a big jump vs just sliding into the groove.

So I found a blank side of an album and lowered the stylus onto the surface and it immediately slid all the way across the surface towards the spindle as though no antiskate were in play. I then disengaged the antiskate weight and experienced the same (expectedly so). But there seemed to be little or no difference between antiskate being engaged/disengaged.

So I engaged the weight again and lowered the stylus, but this time I placed a little extra force on the weight with my finger and was able to get the tonearm to stay in position--applicable antiskate force in play with this extra force. Of course, I have no way of measuring how much extra weight I applied.

The help I need:
Why is the recommended antiskate parameters set by pro-ject seemingly having no effect?
Is something else wrong?
The table and tonearm are obviously manufactured to handle this level of VTF, no?
The tonearm wires don’t appear to be impeding the arm movement.
What can I do to remedy this?
Do I need to do something to remedy this?
I wonder if I’m causing harm to the cantilever with what appears to be no antiskate, yet the music sounds great and the Analogue productions test LP record antiskate tracks "sound" equal to my ears. (But my ears aren’t young anymore, so I don’t think I can place full confidence in that audible test).

Any thoughts, suggestions would be greatly appreciated.
cabalaska

Showing 3 responses by mijostyn

mijostyn's avatar
mijostyn
8,229 posts
 
Cabalska, a likely problem is that the arm was installed incorrectly or the hole for the arm is out of spec. You have to measure the overhang. Check Pro-Jects spec for that arm. If the arm is located too close to the spindle it will skate incessantly. It the arm tube is longer than it should be the same thing will happen. Otherwise you have been doing all the right things. On a groove-less record the arm should drift slowly towards the spindle at the end of the record. 
The anti skating force should be 10% of the VTF. The skating force will decrease slightly as you go towards the center of the record. It does not decrease at the null points. That is just lay instinct. 
If the arm is in spec then somebodies math is wrong and you just add weight until you get the right effect. Or you could tell Pro-Ject that the table is defective and you would like another one. Actually measuring the anti skating force is possible but the devices to do it are either expensive (the WallySkater) or unavailable (my Gizmo). Trying to gauge your particular problem with a test record would be difficult but you could try it.
Lewm is correct in that without anti skating the right channel (outside) groove will miss-track and distort first, too much and the left or inside groove will distort first.
Although anti skating is a ball park proposition it is extremely important for stylus and record wear not to mention sound quality. As the force drifts to far one way or the other it pushes the cantilever into a non-linear zone where moving the stylus one way takes more force than moving it the other. It also displaces the coils, magnet or iron out of the center of the magnetic gap. Any asymmetry is unfavorable for stereo reproduction. If there is a reason straight tangential arms sound better the lack of any skating forces is a more likely candidate than a reduction in tracking error.
God luck in figuring it out. Most people would never have noticed there was a problem.

mijostyn's avatar
mijostyn
8,229 posts
 
@lewm , I did not say that skating will decrease linearly over the record. The force is waxing and waning depending on modulation. In average it decreases slightly towards the end of the record playing surface. If the arm could get to the spindle it would increase quite dramatically but not out in the run out groove.  Skating is present everywhere and is in average substantial. As for the 10% of VTF that is not my figure. 9 to 11% is the range generally accepted by the industry and used to calibrate their devices. The Wallskater   https://www.wallyanalog.com/wallyskater  measures this in a clever (but expensive) way. I measure it directly just by turning the force 90 degrees into a stylus gauge. Not rocket science. I am taking it on faith that around 10% of VTF is a good place to be. It is a very difficult thing to ascertain. Just because a certain setting produces the lowest distortion on one test record does not mean it will do the same on any album. Somewhere in that area +- 10% seems reasonable. You can easily hear what happens if you stray to far one way or the other on any test record. At any rate it is nice to have a number to work to. That way I can make sure I am right on something I can not possibly be right on on?

Don't get me started on VPI arms and no antiskating. That marketing stunt made sure I would never look at a VPI product.

cabalaska, make sure that arm got mounted correctly and check the arm length and overhang!!
mijostyn's avatar
mijostyn
8,229 posts
 
@lewm, absolutely. It has always been arbitrary. I suppose that is why I like the spec of 9 to 11% of VTF. I know for certain what I am setting it to which is psychologically comforting. Certainly, skating is basically proportional to VTF. I think we all agree on that. Intervening factors such as modulation, geometry and a tiny degree speed move it one way or the other. I am not sure where the 9 to 11% figure comes from. I'll try to look into that. This all started with an Analog Planter review of the WallySkater which measures the anti skating force as a percentage of VTF. It is a flimsy plastic contraption (A nicely made one) that could be made in China for $10.00 but is sold for almost $300. So I set out to make a device with $45.00 worth of parts that would be easier to use and based it on the 9 to 10% figure Wally Tools uses. I'll get back.

@stringreen, I hate to tell you this but trying to put anti skating on that arm is like wrestling an alligator in a bathtub. You should trade it in for VPI's Gimbal Fat Boy tonearm. You will not hear much difference with or without anti skating until the right channel starts miss tracking on heavily modulated passages. You can overcome this by increasing VTF and thereby compound the problem of groove and record wear. Stare at the cantilever from the front of the tonearm. Line it up perfectly with the middle of the cartridge by adjusting your line of sight then lower the stylus onto the record with the lift. As the stylus contacts the record (this is with anti skate defeated) the cantilever will immediately appear to drift to the outside relative to the cartridge as it leans on the inside left channel groove wall. Does this seem like a good thing to you?
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